• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.158.5-158
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• 2001

Monopulse active homing radar requires velocity and angle information of target to track fast moving target. Target velocity can be estimated by measuring the frequency shift between transmitted and received frequencies. Angle information is obtained by measuring boresight error. Measurement of doppler frequency component in received signal is done through FFT analysis and interpolation algorithm for fine tuning. Boresight errors in azimuth and elevation axes are proportional to the power of each difference channel relative to sum channel. The target signal power in difference channel is estimated more precisely by measuring the power of FFT result cell of maximum ...

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.11
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• pp.511-518
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• 2005

This paper presents the design and drive characteristics of a switched reluctance motor for an electric power pallet vehicle. The designed switched reluctance motor is redesigned by using the finite element analysis(FEA) as a variation of the pole-arc angle for the purpose of an electric power pallet vehicle performance. The output power and torque characteristics of a switched reluctance motor are variable by switching angles of the commutator. Therefor this paper is studied about relationship between the output power and torque characteristics of a switched reluctance motor according to switching angles. The output power of the characteristic point of an electric power pallet vehicle has been shown by experiment. The designed motor drive system operates with the low voltage and high current with using the battery. The core and frame temperatures were described. In this paper, the designed motor is shown better drive characteristics than the DC motor from the rated to maximum, which is verified by the finite element analysis and experimental results.

• Journal of IKEEE
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• v.26 no.2
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• pp.211-218
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• 2022

This paper presents a S-band phased array antenna system for receiving LEO satellite telemetry signals. The proposed antenna, which is performed to be beam-tiled along the elevation direction, consists of 16 sub-array assemblies, 16 active circuit modules, a perpendicular feed network and a control/power unit. In order to precisely track an LEO satellite, the developed antenna is placed with its elevation axis along the projected trajectory of the satellite on the earth. The center of antenna aperture is facing to the maximum elevation angle in the LEO trajectory. The beam-tilted angles for tracking LEO satellite are obtained by calculating accurately satellite points. Satellite tracking measurements are carried out in the range of ±30° with the respect to the maximum elevation angle. The S/N ratio of 16.5 dB and the Eb/No of 13.3 dB at the maximum elevation angle are obtained from the measurements. The measured result agrees well with the pre-analyzed system margin.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.588-594
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• 2009

The maximum power point operation point(MPPOP) of photovoltaic(PV) power generation systems changes with varying atmospheric conditions such as temperature, solar radiation. For achieving a high efficiency in PV system, it is very important for PV system to track the MPPOP correctly according to operation condition. Although the MPPT(maximum power point tracking) algorithm which applied P&O(Perturbation & Observation) or IncCnd(Incremental Conductance) algorithm tracks the MPPOP efficiently, its efficiency drops noticeably in case that the incidence angle of PV panel on buoy changes rapidly. To solve this problem, this paper proposes maximum power point searching and tracking algorithm(MPPST). The proposed algorithm set the specific area and measures the PV voltage at the same interval. The proposed algorithm have been obtained high efficiency than P&O algorithm through ocean experiment.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.89-91
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• 2008

The photovoltaic industry is growing at a tremendous speed. And it can be one of the key factors for success in the photovoltaic business to choose a suitable system, and setting it up right so as to get a maximum efficiency of the site. Therefore, it is regarded to be necessary to research the efficiency of systems to catch maximum photovoltaic energy. In this research, the expected power generation efficiencies are analysed, and compared with each other. This research considered the direct sunlight only, and the angle between the direction of solar panel and sunlight as factors to affect the power generation. Therefore, only rough analyses and estimations are found on 3 systems of fixed system, double-axes tracking system, and horizontal tracking system.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.159-161
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• 2001

This study is for the pitch control of blade, used in most horizontal-axis wind turbine systems, to sustain the maximum power output supplied to grid. The control of a blade can be divided into a stall regulation and a pitch control methods. The stall regulation method using an aerodynamic stall is simple and cheap, but it suffers from fluctuation of the resulting power. Pitch control method is mechanically and mathematically complicated, but the control performance is better than that of the stall regulation method. In this paper 2.5MW MOD-2 wind turbine system is adopted to be controlled by a pitch controller with PI method. The simulation performed by MA TLAB will show the variation of frequency, generator output, and pitch angle.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.37-40
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• 2001

This paper is suggested an optimal switching angle of a switched reluctance motor drive system for maximum energy ratio. A new magnetizing method with a low-frequency increasing the energy conversion ratio that is related to the efficiency of motor is proposed As results, it improves the efficiency about 2[$\%$]. And a torque ripple is also reduced compared with that of the conventional switching angle magnetizing approach. In order to start softly regardless of a large ripple torque, the profile of phase current is predicted and current control mode was adapted when it is operated under the starting speed.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.224-227
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• 2004

The goal of this paper is optimal switching angle of switched reluctance motor drive system for maximum energy ratio. A new magnetizing method with a low-frequency increasing the energy conversion ratio that is related to the efficiency of motor is proposed. As results, it improved the efficiency about $2[\%]$. And a torque ripple is also sufficiently reduced compared with that of the conventional switching angle magnetizing approach. In order to start softly regardless of a large ripple torque, the profile of phase current is predicted by the ANFIS, and current control mode was adapted when it is operated under the starting speed. Variable implementations on the fields will guarantee the more practical drive system.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.113-114
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• 2002

Radial, tilting 12-pad proceeding bearings are applied as the radial bearings of vertical rotors of water turbines. The mean loads are stable at the peripheral speeds of proceeding reaching 50 m/s. The operation of tilting 12-pads proceeding bearing has been introduced at the assumption of adiabatic oil film. The oil film pressure, temperature and viscosity distributions have been obtained by iterative solution of the Reynolds', energy and viscosity equations. The resulting oil film force, minimum oil film thickness, power loss, oil flow, maximum oil film pressure, maximum temperature have been computed for different load angle of bearing.

• Journal of Biosystems Engineering
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• v.36 no.3
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• pp.171-179
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• 2011

Facing the current hikes of labor wage and high oil price, it is needed to have energy-saving machinery which also enables us precise farm operations. Thus, it was necessary to develop a safe machine which allows secure and pleasant works along orchard slopes. In this study, a lifting utility with balance-controlled platform was developed. The platform utility could maintain to level the workbench while driving along slopes. Even the machine body was driven at the tilt angle ranges of ${\pm}20^{\circ}$, the platform bench could be maintained within ${\pm}0.5^{\circ}$ of a gimbal angle. In addition, the machine lifted up to 2.0 m using an electric-hybrid driving mechanism with a low noise. A tandem hybrid power source was developed with a DC 72 V, 100 AH for the Deep-Cycle batteries, charged with 3.5 kW gasoline generator as an auxiliary power source. HST, which is one of the CVT's, was adopted as a transmission device, and a crawer track was used for the safety of the vehicle against tip-over. The maximum lifting height of platform was is 2,500 mm, and the maximum extendable width was 2,900 mm.